Insights into the antimicrobial efficacy of Coleus aromaticus essential oil against food-borne microbes: Biochemical and molecular simulation approaches

Abstract

The study reported the antimicrobial efficacy of chemically characterized Coleus aromaticus essential oil (CEO) against food-borne bacteria, molds (Aspergillus flavus), aflatoxin B₁ (AFB₁) and explored its mechanism of action using biochemical and molecular simulation approaches. The chemical profile of CEO was explored by Gas chromatography-mass spectrometry (GC-MS) analysis, which revealed thymol (46.0%) as the major compound. The minimum inhibitory concentration values of CEO for bacterial species Escherichia coli, Salmonella enterica, Bacillus cereus, and Shigella flexneri was found to be 0.9 μl/ml, 0.7 μl/ml, 0.16 μl/ml, and 0.12 μl/ml respectively. The MIC value for A. flavus and AFB₁ contamination was 0.6 μl/ml. The DPPH radical scavenging activity of CEO was recorded with IC₅₀ 0.32 μl/ml. Biochemical and computational approaches (docking and dynamics simulation) have been performed to explore the multi-faceted antimicrobial inhibitory effects of CEO at the molecular level, which shows the impairment in membrane functioning, leakage of cellular contents, release of 260-nm absorbing materials, antioxidative defense, carbon catabolism and vital genes (7AP3, Nor1, Omt1, and Vbs). The findings indicated that CEO could be used as natural antimicrobial agents against food-spoilage bacteria, A. flavus and AFB₁ contamination to extend the shelf-life of food product and prevention of food-borne diseases.

Keywords: Aflatoxin B(1); Coleus aromaticus; Computational approaches; Essential oil; Food-borne microbes.